MOLLUSCA FROM JUAN FERNANDEZ AND EASTER ISLAND 



229 



bilicus (equalling about the third of the shell diameter); suture deep, whorls 

 narrow. Sculpture: protoconch (i V2 apical whorl) distinctly spirally striate, 

 the following whorls very closely constulate (about 

 50 — 60 costae in one millimetre), interstices with 

 one or a few fine longitudinal ribs and with obso- 

 lete microscopical spiral striae. Aperture lunate, 

 without armature, lip thin. Colour of the thin cuti- 

 cula horn-brown. Diameter i mm; whorls 3^/2. 

 One somewhat fragmentary specimen of this 

 shell was obtained in earth on a specimen o{Eiiphrasia 

 in Masafuera, about i lOom above the sea,and another, 

 entire sp., d. 1,5 mm, whorls 3 ^/4, in earth from the Sanchez Plateau, 515 m, thick 

 forest (C. Skottsberg, ^^/2 1917). The species has a sculpture similar to that 

 of E. (Charopa) prestoni Sykes, from N. Zealand (cf. Suter, 191 3, Man. N. Zea- 

 land Moll., p. 727), but the costellae are much denser. 



Fig. 7. Endodonta (Charopa) 

 masafuerae 11. sp. X 50. 



Endodonta (Thaumatodon) occulta n. sp. PI. 9, figs. 30 — 32. — Shell 

 discoidal, with flattened, only slightly convex spire, and a broad perspective 

 umbilicus; whorls 4^/4, convex and rounded, with impressed suture. Colour 

 chocolate with a few irregular grayish stripes. Sculpture: first i ^/2 apical 

 whorls quite smooth, the following ones with distinct and regular radial riblets, 

 about 20 in a millimetre; interstices with fine radiating lines. Aperture semi-lunate, 

 slightly oblique (upper lip somewhat more produced), lips simple; interior of 

 aperture with one strong parietal plica and in the outer wall a basal tooth as 

 well as an upper palatal tooth, both combined with a low vertical list; all teeth 

 deep down in the aperture and a little difficult to observe. Dimensions: diam. 2, 

 d. of last whorl 0,6, of umbilicus 0,8 mm; height 0,8, h. of aperture 0,7 mm. 



Localities: Masatierra: The Yunque quebrada, the lower part, i sp., figs. 30 — 

 32. — Puerto Ingles, about 300 m, thin forest, 3 fragmentary shells (Aug. 1917). 



The shells were all empty, thus the radula could not be examined. 



The peculiar dentition of the aperture shows some reference to the section 

 Thaumatodon which is chiefly Polynesian in its distribution. However, all these 

 species have their apertures multidenticulate. A number of three teeth with a 

 similar position as in the present species exists only in a few forms: E. philippi- 

 nensis Semper from the Philippines, E. tau Pfeifler from Auckland, New Zea- 

 land, though the sculpture of the last-named is unlike that of E. occidta. 



Amphidoxa marinorella Pfeifler. — Masatierra (^V4 1917), i sp., d. 2,8 mm, 

 in leaves; Aug. 191 7: Rabanal, in the bottom, about 100 m above sea, some 

 sps., d. 3; down in the quebrada, under leaves, 2 shs., d. 4, and about 300 m, 

 numerous sps., d. 3,3. — Piedra Agujeriada Valley, many sps., d. 3,3. — Pangal, 

 on ferns and under leaves, i sh., d. 3. — The Portezuelo quebrada, about 300 m 

 above sea, on ferns, 2 small sps., and 200 m, among leaves and on ferns, 5 sps., 

 d. 3. — Centinela Ridge, about 500 m, under ferns, numerous sps., d. 3,3. — 

 Salsipuedes Ridge, about 350 m above sea, 5 sps., d. 3,4. — Beneath Damajuana, 

 thick forest, about 300 m, some small sps. — Puerto Ingles, about 400 m, thick 

 forest, a few small sps. 



